Fig 4. C14dm‾ parasites show compromised cellular respiration.

(A-C) Log phase promastigotes were incubated in a mitochondrial respiration buffer (A-B) or DMEM (C) and oxygen consumption rates (OCR) were determined using the MitoXpress probe as described in Materials and Methods. Buffer only and buffer with probe (no cells) were included as blanks (A). In A and C, fluorescence signals (in arbitrary units or A.U.) were measured every 90 s. In B, the relative OCR from the experiments in A was calculated by subtracting the 0 min reading from the 15 min reading. WT parasites treated with antimycin A (AA) were included as controls. (D) Cellular ATP contents in log phase promastigotes were measured after 1 hour incubation in an assay buffer (21 mM of HEPES, 0.7 mM of Na₂HPO4, and 137 mM of NaCl, pH 7.2) in the absence or presence of glucose (Glu, 5.5 mM), sodium pyruvate (Pyr, 5.5 mM), 2-deoxy-D-glucose (2DG, 5.5 mM), or sodium azide (NaN₃, 20 mM). All experiments were repeated three or four times and error bars represent standard deviations.